This grant is used to study the following: heterogeneity of genetic eye diseases, their segretation analysis, linkage assignment of autosomal dominant and X-linked eye diseases, as well as screening of inbred populations for ocular diseases. This latter approach is used to detect the presence of major genes in visually handicapping disorders versus environmental influences, and to delineate clear nosologic entities, presumably of autosomal recessive inheritance in an environmentally homogenous population with a high inbreeding coefficient.